ultraembedded/fat_io_lib

FAT16/32 File System Library

Github: http://github.com/ultraembedded/fat_io_lib

Intro

Designed for low memory embedded systems back in 2003, this project is a multi-purpose platform independent C code implementation of a FAT16 & FAT32 driver with read & write support.

The library provides stdio like interface functions such as fopen(), fgetc(), fputc(), fread(), fwrite() etc, allowing existing applications to be ported easily using a familiar API.
The project is aimed at applications which require file system support such as MP3 players, data loggers, etc and has a low memory footprint with customizable build options to enable it to run on platforms such as the Atmel AVR, ARM & PIC microcontrollers.

The source code is available for free under GPL license, or alternatively, with a commercial compatible license for a small donation.

This library has been used in many open source projects including;

Aleph - Open source sound computer.
IV:MP - Grand Theft Auto: IV multiplayer game mod.
hxcfloppyemu - HxC Floppy Drive Emulator.

Features

Standard file I/O API (fopen(), fread(), fwrite(), etc)
FAT16/FAT32 support (read + write)
Long filename support (optional)
Format function (optional)
Directory listing (optional)
Buffering & caching for higher performance (optional)

API

The following file IO API is provided:

fopen
fclose
fread
fwrite
fputc
fputs
fgetc
fflush
fgetpos
fseek
ftell
feof
remove

Just add sector read & write functions for the media/platform you are using for a complete file system!

Testing

Each release of the project is tested using self verifying test benches to ensure validity and to protect against regressions (not currently released).

Commercial

If you would like to use this code in a commercial project with a closed source compatible license, please contact me.

Configuration

See the following defines in src/fat_opts.h:

FATFS_IS_LITTLE_ENDIAN 	[1/0]
  Which endian is your system? Set to 1 for little endian, 0 for big endian.

FATFS_MAX_LONG_FILENAME	[260]
  By default, 260 characters (max LFN length). Increase this to support greater path depths.

FATFS_MAX_OPEN_FILES 	
  The more files you wish to have concurrently open, the greater this number should be.
  This increases the number of FL_FILE file structures in the library, each of these is around 1K in size (assuming 512 byte sectors).

FAT_BUFFER_SECTORS
  Minimum is 1, more increases performance.
  This defines how many FAT sectors can be buffered per FAT_BUFFER entry.

FAT_BUFFERS
  Minimum is 1, more increases performance.
  This defines how many FAT buffer entries are available.
  Memory usage is FAT_BUFFERS * FAT_BUFFER_SECTORS * FAT_SECTOR_SIZE

FATFS_INC_WRITE_SUPPORT
  Support file write functionality.

FAT_SECTOR_SIZE
  Sector size used by buffers. Most likely to be 512 bytes (standard for ATA/IDE).

FAT_PRINTF
  A define that allows the File IO library to print to console/stdout. 
  Provide your own printf function if printf not available.

FAT_CLUSTER_CACHE_ENTRIES
  Size of cluster chain cache (can be undefined if not required).
  Mem used = FAT_CLUSTER_CACHE_ENTRIES * 4 * 2
  Improves access speed considerably.

FATFS_INC_LFN_SUPPORT 	[1/0]
  Enable/Disable support for long filenames.

FATFS_DIR_LIST_SUPPORT 	[1/0]
  Include support for directory listing.

FATFS_INC_TIME_DATE_SUPPORT  [1/0]
  Use time/date functions provided by time.h to update creation & modification timestamps.

FATFS_INC_FORMAT_SUPPORT
  Include support for formatting disks (FAT16 only).

FAT_PRINTF_NOINC_STDIO
  Disable use of printf & inclusion of stdio.h

Interfacing to storage media

-----------------------------------------------------------------
int media_read(uint32 sector, uint8 *buffer, uint32 sector_count)
-----------------------------------------------------------------
Params:
    Sector: 32-bit sector number
    Buffer: Target buffer to read n sectors of data into.
    Sector_count: Number of sectors to read

Return: 
    int, 1 = success, 0 = failure.

Description:
    Application/target specific disk/media read function.
    Sector number (sectors are usually 512 byte pages) to read.

-----------------------------------------------------------------
int media_write(uint32 sector, uint8 *buffer, uint32 sector_count)
-----------------------------------------------------------------

Params:
    Sector: 32-bit sector number
    Buffer: Target buffer to write n sectors of data from.
    Sector_count: Number of sectors to write.

Return: 
    int, 1 = success, 0 = failure.

Description:
    Application/target specific disk/media write function.
    Sector number (sectors are usually 512 byte pages) to write to.


-----------------------------------------------------------------
Use the following API to attach the media IO functions to the File IO library;

fl_attach_media(media_read, media_write);

History

v2.6.11 - Fix compilation with GCC on 64-bit machines
v2.6.10 - Added support for FAT32 format.
v2.6.9 - Added support for time & date handling.
v2.6.8 - Fixed error with FSINFO sector write.
v2.6.7 - Added fgets(). Fixed C warnings, removed dependency on some string.h functions.
v2.6.6 - Massive read + write performance improvements.
v2.6.5 - Bug fixes for big endian systems.
v2.6.4 - Further bug fixes and performance improvements for write operations.
v2.6.3 - Performance improvements, FAT16 formatting support. Various bug fixes
v2.6 - Basic support for FAT16 added
v2.5 - Code cleaned up. Many bugs fixed. Thread safety functions added.
v2.x - Write support added as well as better stdio like API.
v1.0 - Rewrite of all code to enable multiple files to be opened and provides a better file API.
v0.1b - fopen(), fgetc(), fopenDIR() using new software stack for IDE drives and FAT32 access.
v0.1a - First release; fopen(), fgetc() unbuffered reads.... (27/12/03)

ultraembedded / fat_io_lib